The following structure is typically adapted in a printer head of an inkjet printer. An ink is supplied from an ink supply source (ink tank) to an ink supply port of a head unit via an ink flow channel, and a predetermined pressure is selectively applied, using a plate-shaped piezoelectric actuator arranged on the head unit, to a pressure chamber that communicates with a plurality of nozzle pores and the ink is discharged from each nozzle pore.
A flow channel arrangement (ink tube) made of resin and constituting the ink flow channel couples the ink supply port of the head unit and the ink flow channel. The flow channel arrangement is coupled to the ink tank. Consequently, the ink is supplied from the ink tank to the head unit via the flow channel arrangement.
Meanwhile, a technique is known in which a plurality of the ink supply ports is arranged in the head unit and the ink is supplied to the ink supply ports via branched flow channels that branch from one ink flow channel (see, for example, Patent Document 1).
Such a structure is employed to supply the ink to a plurality of locations on a nozzle plate in a divided manner to thereby uniformly discharge the ink from an entire surface of the nozzle plate that is arranged below the head unit. That is, a device that employs this technique includes one ink flow channel that communicates with the ink supply source, and the flow channel arrangement constituting a plurality of the branched flow channels that branch out from the ink flow channel and communicate with the corresponding ones of the ink supply ports of the head unit.
When the inkjet printer is operated for the first time, or when the printer head is replaced, charging of the ink into the printer head (so called initial charging) is performed, for example, in the following manner. That is, the surface of the nozzle plate is air-tightly covered with a cap, and air inside the cap is sucked by using a pump (see, for example, Patent Document 1).
The conventional charging method involving simply continuing sucking of the ink has a problem that, as shown in FIG. 5, air may be left inside the flow channel arrangement. This air hampers the supply of the ink during printing and causes a discharge failure.